It is well known that field emission devices (FEDs) might be used to display images similar to the images displayed on CRTs. It is also known that to display an image using an FED that the volume surrounding the FED might have to be evacuated to permit emitted electrons to freely travel through the volume surrounding the FED and impinge upon an image faceplate or other surface that can generate visible light. An enclosure for an FED imaging device or a field emission display device should permit the FED to be hermetically sealed in an evacuated volume at very high vacuum levels.
Many prior art vacuum sealing techniques employ epoxies or glass frits to effect a desired vacuum seal between a housing and a housing cover. Epoxy seals are not well-suited to sealing applications requiring vacuum levels, or residual pressure, as low as 1.times.10.sup.-6 Torr. because the epoxy may leak or outgas into the evacuated volume. Glass frits do not outgas to the extent that epoxies do and are known to withstand very high vacuum levels but glass frits do not bond well to many materials, including silicon upon which many field emission device displays are fabricated, making glass frit unsuitable as a sealing material in combination with most field emission display substrate materials.
Since FEDs, used in field emission displays operate in very high vacuum environments, typically less than 1.times.10.sup.-6 Torr, there exists a need for a new display package and package sealing method that overcome at least some of the shortcomings of the prior art.